1. Field of the Invention
The present invention relates to a semiconductor light-emitting device, a manufacturing method thereof, and a lamp, and more particularly, to a semiconductor light-emitting device and a manufacturing method thereof which are capable of providing a lamp having a small output decrease in a high temperature environment.
2. Description of Related Art
As a semiconductor light-emitting device such as an LED (Light-Emitting Diode) used in a lamp, a technique has been used in which a group III nitride semiconductor layer is stacked on a sapphire single-crystal substrate.
In recent years, as such a semiconductor light-emitting device, a technique has been proposed in which recesses and projections are formed on a surface of a sapphire substrate and a group III nitride semiconductor layer is grown thereon (for example, refer to JP-A-2002-280611). In such a semiconductor light-emitting device, since an interface between the sapphire substrate and the group III nitride semiconductor layer is formed in a concave and projection shape, light on the interface is irregularly reflected due to different refractive indexes of the sapphire substrate and the group III nitride semiconductor layer, and thus it is possible to reduce the containment of light in the light-emitting device and to enhance light extraction efficiency.
Furthermore, as a group III nitride semiconductor light-emitting device having high light extraction efficiency, a technique has been proposed in which a group III nitride semiconductor layer is grown on a (0001) c-plane surface of sapphire substrate and an upper surface formed with a plurality of projection portions are formed (for example, refer to JP-A-2009-123717).